Digital leaching dosing circulating system and method based on sensing technology

Abstract

The invention discloses a digital leaching dosing circulating system and method based on a sensing technology. The digital leaching dosing circulating system comprises a soil leaching system, a water treatment system and a monitoring system. The soil leaching system is used for smashing and leaching soil, the water treatment system is used for recycling leaching wastewater, and the monitoring system comprises weighing monitoring of the feeding unit, inlet and outlet flow monitoring of the support pool area and water quality monitoring. According to the present invention, with the mathematical relationship between the water quality characteristics of the leaching stock solution, the soil leaching waste liquid and the water treatment leaching liquid and the leaching concentration content, the leaching agent concentration is indirectly determined by using the water quality monitoring amount, such that the real-time monitoring of the key parameters in the soil leaching process is achieved, and the quality control of the leaching process is enhanced. The existing online monitoring, data acquisition, configuration analysis and automatic control technologies are integrated and applied to the field of soil leaching, so that comprehensive automatic control of soil leaching is further realized, and intelligent regulation and reutilization of a leaching agent are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of key process monitoring and reagent recycling of heavy metal contaminated soil leaching, and relates to a digital leaching and dosing circulation system and method based on sensor technology, in particular to a method capable of real-time monitoring of leaching reagent concentration during the leaching process. Background Art

[0002] Data in environmental remediation construction is mainly collected, processed, simulated and fed back manually, which has limitations and subjectivity, and is not conducive to the accurate collection and timely feedback of construction information, nor to the optimization and decision-making of construction parameters. With the promotion and application of digital technology, various regions have put forward clear definitions and requirements for the key process parameters and monitoring of ex situ leaching remediation technology for heavy metal contaminated soil, and the demand for direct dynamic monitoring of key parameters such as circulation / supplementary water flow and leaching wastewater flow is increasing. At present, direct dynamic monitoring of circulation / supplementary water flow parameters has been realized, but key parameters such as the amount of reagents used / agents added in the leaching and wastewater treatment sections cannot be directly obtained and dynamically monitored. The concentration of the eluent is the most critical factor affecting the leaching efficiency and leaching cost of heavy metal contaminated soil. In most cases, leaching remediation does not consider the reuse of leaching agents, and needs to continuously replenish newly configured eluents during feeding, and the cost of leaching agents remains high; even if the reuse of leaching agents is considered, the amount of lost agents cannot be determined, and the leaching efficiency is guaranteed by excessive replenishment.

[0003] The present invention analyzes the water balance and reagent balance in the elution process, and adjusts and controls the reagent replenishment amount and clean water through sensors, automatic valves and other controllers to achieve a dynamic balance between reagent circulation and replenishment. The loss of eluent in the elution process and the necessary replenishment amount are calculated through the balanced data, thereby effectively controlling the elution cost and potential secondary pollution. Summary of the invention

[0004] Based on the above problems, the present invention provides a digital leaching and dosing circulation system and method based on sensing technology, which utilizes the mathematical relationship between the water quality characteristics (pH, conductivity, COD, etc.) of the leaching stock solution, the waste liquid after soil leaching, and the leaching liquid after water treatment and the leaching concentration content, and uses the water quality monitoring volume to indirectly determine the concentration of the leaching agent, thereby realizing real-time monitoring of key parameters in the soil leaching process and strengthening the quality control of the leaching process. The existing online monitoring, data acquisition, configuration analysis and automatic control technologies are integrated and applied to the field of soil leaching, further realizing comprehensive automated control of soil leaching, and realizing intelligent regulation and reuse of leaching agents. The specific technical scheme is as follows:

[0005] In a first aspect, the present invention provides a digital leaching and dosing circulation system based on sensing technology, which includes three parts: a soil leaching system, a water treatment system and a monitoring system.

[0006] The soil leaching system is used to perform leaching and remediation of heavy metal contaminated soil, including a feeding unit, drum screening, vibration screening, cyclone classification and cyclone elution, and a dehydration unit;

[0007] The water treatment system is used to reuse the leaching wastewater, precipitate the heavy metals eluted in the wastewater, and release the leaching agent by treating the leaching wastewater, including: a regulating tank, a dosing tank, a sedimentation tank, and a support tank connected in sequence, and the inlet of the regulating tank is connected to the outlet of the dehydration unit;

[0008] The monitoring system is used to monitor key data in the soil treatment and water treatment processes, and to calculate the loss of elution agents and the necessary replenishment during operation, including weighing monitoring of the feed unit, inlet and outlet flow monitoring of the support pool area, and water quality monitoring.

[0009] Preferably, the specific compositions of the above three systems are as follows:

[0010] (1) Soil washing system

[0011] The feeding unit includes an ALLU bucket, a loading hopper and a conveyor connected in sequence. The ALLU bucket separates the construction waste from the contaminated soil; a weighing monitor (such as a belt weigher) is installed on the conveyor to monitor the feed volume S of the heavy metal contaminated soil, and this data is the basis for controlling the water flow rate of the support pool;

[0012] The drum screen is divided into a drum machine, and the vibrating screen is divided into a high-frequency vibrating screen. The drum machine is connected to the water outlet of the support pool, and the heavy metal contaminated soil and the elution liquid are mixed and slurried according to the designed liquid-solid ratio (preferably 6:1); after the contaminated soil is screened by the drum screening unit and the vibrating screening unit, stones (1.5-20mm) and granular materials (about 1.5mm sand and gravel) are removed from the soil;

[0013] The cyclone classification and cyclone elution unit includes primary cyclone elution, primary cyclone separation, secondary cyclone elution, secondary cyclone separation and mechanical stirring elution; the dehydration unit includes a dehydration screen, a cyclone concentration and a plate and frame filter press;

[0014] In terms of specific connections, the first-level cyclone elution inlet is connected to the mud outlet of the vibrating screen, the first-level cyclone elution outlet is connected to the first-level cyclone sorting inlet, the coarse material outlet of the first-level cyclone sorting is connected to the mechanical stirring and eluting, and the fine material outlet is connected to the second-level cyclone elution inlet; the mechanical stirring and eluting outlet is connected to the second-level cyclone sorting inlet, the coarse material outlet of the second-level cyclone sorting is connected to the dewatering screen, and the fine material outlet is connected to the second-level cyclone elution inlet; the outlet of the second-level cyclone elution is connected to the cyclone concentration device, the supernatant outlet of the cyclone concentration is connected to the regulating tank inlet, the sludge outlet of the cyclone concentration is connected to the plate and frame filter press inlet, and the wastewater outlet of the plate and frame filter press is connected to the regulating tank of the water treatment system.

[0015] (2) Water treatment system and monitoring system

[0016] The effluent from cyclone concentration and plate and frame filter press is leaching wastewater, which is first homogenized in the regulating tank, then dosed in the dosing tank, and finally discharged after coagulation and sedimentation in the sedimentation tank.

[0017] The support pool is used to hold the eluent, and three inlet flow rates and two water quality monitors are set at its inlet, and one outlet flow rate and one water quality monitor are set at its outlet; the outlet flow rate and water quality are the eluent Q0 and f(C0) adjusted in the support pool; the three inlet flow rates and two water qualities are: ① treated water from the sedimentation tank Q1 and f(C1), ② supplemented eluent water Q2 and f(C2), and ③ clean water Q3. Q0, Q1, Q2, and Q3 are monitored and transmitted in real time by electromagnetic flowmeters, and f(C0), f(C1), and f(C2) are monitored, processed, and transmitted in real time by corresponding water quality sensors.

[0018] Specifically, electric valves need to be installed at the three positions of the bracket pool water outlet Q0, supplementary elution liquid Q2, and clean water Q3 to adjust the water outlet. The water outlet should be adjusted in time according to the real-time monitored flow rate and water quality to achieve dynamic balance in the entire soil elution-water treatment process.

[0019] Furthermore, the support pool should store at least enough eluent for continuous operation for 1.5 hours, V≥1.5×Q0. The basic relationship between water quality and concentration should be established under small or pilot tests according to different soil conditions.

[0020] The second aspect of the present invention provides a working principle for realizing a digital elution and dosing cycle, combined with Figure 1 ,as follows:

[0021] The contaminated soil is initially screened by the drum screening unit and the vibration screening unit in turn to remove construction waste, stones and granular materials from the soil. The soil is then mixed with the eluent in the drum screening unit according to the designed liquid-solid ratio to make a pulp. After the initial screening, the slurry enters the cyclone classification and cyclone elution stages. The cyclone classification further subdivides the soil into smaller granular materials. The cyclone elution ensures the full mixing reaction of the granular materials and the eluent through high-intensity physical elution. The coarse granular materials of the cyclone classification are dehydrated by the dewatering screen and discharged. The slurry containing fine granular materials enters the solid-liquid separation unit after full mixing reaction. The slurry is pre-dehydrated by cyclone concentration and then deeply dehydrated by the plate and frame filter press to form a mud cake (clean soil). The effluent from the filter press enters the regulating tank. After the precipitator is added with chemicals, the treated clear liquid flows into the support pool for storage. The clear liquid is supplemented with chemicals and clean water in the support pool and then pumped to the drum screen to mix with the contaminated soil to make a pulp. The above process forms a cycle.

[0022] In the above treatment process, the soil is sent to the drum screen by a conveyor. A quality monitoring device needs to be installed on the conveyor to measure the soil feed amount S in real time. A flow meter can be installed at the outlet of the regulating tank to measure the leaching wastewater flow in real time. A flow meter can be installed between the water treatment dosing tank and the dosing barrel to measure the added agent flow in real time. A flow meter and a water quality monitor need to be installed at the outlet of the sedimentation tank to measure the flow Q1 and water quality f(C1) of the clear liquid after water treatment in real time. A flow meter needs to be installed at the agent and clean water replenishment port of the support pool to measure the replenishment agent original liquid and clean water flow Q2 and Q3 in real time, and reversely calculate the replenishment agent amount and clean water amount. A flow meter and a water quality monitor need to be installed at the outlet of the support pool to measure the total flow Q0 and water quality f(C0) of the leaching liquid in real time, and combine the soil feed monitoring data to ensure that the liquid-solid ratio of the leaching process is consistent with the design value. Among them, there is the following mathematical relationship:

[0023] Q0÷S=L / S

[0024] L / S is the liquid-to-solid ratio set in the repair plan (usually 4:1 to 6:1);

[0025] Q1+Q2+Q3=Q0

[0026] At the support pool, the inflow is equal to the outflow, and the water storage in the support pool is balanced;

[0027] At present, the solute concentration of the solution cannot be directly measured. It takes a certain period of time to get the result through laboratory measurement. Therefore, in the traditional leaching construction process, the circulation dosage of the reagent cannot be determined, which is a construction blind spot. The present invention intends to determine the water quality parameter that best reflects the solute concentration by measuring various water quality parameters in different solvent solution states, and through mathematical fitting of the concentration-parameter value, indirectly determine the instantaneous concentration of the solute by calculating the inverse function of the fitting function, so that the process data can be recorded and the reagent circulation replenishment dosage can be accurately calculated, that is:

[0028] Characteristic water quality parameter = f(C2)

[0029] C2=g(f(C2))

[0030] By analogy, by measuring the water quality parameters f(C1) and f(C0), the concentration of the elution solution C1 and the concentration of the reagent supplement C2 are determined in turn:

[0031] C1=g(f(C1))

[0032] C0=g(f(C0))

[0033] Based on the above principle, the third aspect of the present invention provides a digital elution and dosing circulation method based on sensing technology.

[0034] First, determine the selection and theoretical values ​​of various monitoring parameters. The steps for confirming the plan are as follows:

[0035] (1) Determine the feed rate of contaminated soil according to the treatment capacity of the leaching equipment, and design the leaching agent, leaching agent concentration, leaching liquid-solid ratio and water treatment plan according to the soil pollution characteristics and soil texture;

[0036] (2) Determine the concentration-water quality curves of eluents with different mass fractions, and obtain the concentration-water quality fitting function of the specific eluent according to the measurement results, and select the water quality type with the best fitting effect according to the degree of fit;

[0037] (3) Carry out a small-scale elution test according to the designed eluent-solid ratio, measure the water quality of the elution waste liquid after elution filtration and the elution regeneration liquid after water treatment, and obtain the concentration-water quality curve of the eluent. The concentration is the concentration of the elution stock solution. The concentration-water quality fitting function of the specific eluent is obtained according to the measurement results, and the water quality type with the best fitting effect is selected according to the degree of fit;

[0038] (4) Determine the optimal amount of reagent supplement for the elution regeneration liquid after water treatment, select elution stock solutions with different concentration gradients of 0%, 10%, 20%, 30%, 40%, and 50% as the supplement amount to be added to the elution regeneration liquid after water treatment, and use it as the elution liquid for circulating elution to conduct soil elution test, measure the pollutant content of the soil after elution, and determine the amount of reagent supplement that can meet the pollutant removal rate;

[0039] (5) Determine the replenishment amount-water quality curve of the circulating eluent under different reagent replenishment conditions, and obtain the eluent replenishment amount-water quality fitting function according to the measurement results, that is, water quality parameter value = f(C0) = f'(Q2), and select the water quality type with the best fitting effect according to the fitting degree;

[0040] (6) All the above water qualities are water qualities that can be quickly and directly monitored, including pH, conductivity, COD, turbidity, and color. The fitting results in steps (3) to (5) are the results of repeating the elution process for more than 3 cycles and the control number for more than 2 times. The fitting coefficient R 2 >0.9.

[0041] (7) According to the above steps, determine the eluent, agent concentration, theoretical value of soil feed volume S, liquid-to-solid ratio and theoretical value of eluent flow rate Q0 required for eluting the specific contaminated soil;

[0042] Determine the amount of reagent supplement under circulating elution conditions, and determine the water quality parameters, fitting functions and theoretical values ​​of water treatment effluent C1, supplementary reagent effluent C2, and circulating elution effluent C0;

[0043] Determine the sensors needed for C0, C1, C2 water quality parameters.

[0044] The subsequent implementation method in the system is as follows:

[0045] S1: The soil feed is weighed to obtain the real-time soil feed rate S (t / h). The feed rate is controlled to be within ±10% of the theoretical value. The water flow rate Q0 is controlled to be within ±10% of the theoretical value according to the liquid-solid ratio and the valve. Q0 = S × liquid-solid ratio;

[0046] S2: The leaching wastewater enters the bracket pool after water treatment, and the leaching agent and clean water are supplemented at the bracket pool; f(C0), f(C1), and f(C2) are measured by water quality monitoring at the three inlets and one outlet of the bracket pool, and Q2 is adjusted by the automatic control program to control the monitoring values ​​within the deviation of ±10% of the theoretical value;

[0047] S3: Automatically adjust the clean water flow Q3 according to the conditions of Q0, Q1, and Q2 to complete the water circulation and reagent supplement for soil leaching and wastewater treatment to achieve dynamic balance;

[0048] S4: Through the monitoring input values ​​and fitting functions of water quality parameters at different locations in the configuration simulation software, cumulative monitoring calculations are performed on the input reagents.

[0049] The specific soil treatment steps are as follows: heavy metal contaminated soil is screened by the ALLU bucket to remove construction waste from the soil, and after the drum screening unit screens out stones of 3 to 20 mm, it is mixed with the eluent provided by the support pool according to the designed liquid-solid ratio to make slurry, and then high-frequency vibration screening is performed to remove sand and gravel with a particle size of about 1.5 to 3 mm;

[0050] After the initial screening, the mud enters the cyclone classification and cyclone elution stage. The mixed mud first undergoes high-intensity physical elution at the primary cyclone elution to ensure sufficient mixing and reaction of the granular material and the eluent; then it enters the primary cyclone sorting to separate the particles with a diameter of more than 0.075 mm, and the fine materials below 0.075 mm enter the secondary cyclone elution for further mixing and reaction. The coarse particles enter the stirring elution device for elution and then enter the secondary cyclone sorting device for further classification; after the secondary cyclone sorting, the coarse materials are dehydrated in the dewatering screen to obtain fine sand with a diameter of 0.075 to 1.5 mm. After the secondary cyclone sorting, the fine materials enter the secondary cyclone elution for further elution;

[0051] The mud after secondary cyclone elution is pre-dehydrated by cyclone concentration, and then deeply dehydrated by plate and frame filter press to form clean soil mud cake; the effluent from the filtration enters the regulating tank, and after the addition of chemicals and precipitation, the treated clear liquid flows into the support pool for storage; the clear liquid is supplemented with chemicals and clean water in the support pool and then pumped to the drum screen to mix with the contaminated soil of the feed for pulping.

[0052] This method is suitable for ex situ leaching of heavy metal contaminated soil. The equipment is equipped with a corresponding PLC control cabinet to control the electromagnetic flowmeter, water quality monitor, electric valve and other automatic control instruments involved; according to the existing process route and monitoring and adjustment, the configuration analysis model is set, the monitoring data is collected, and the adjustment and control are performed through the PLC. Preferably, the upper and lower floating ranges of the flow rate and water quality online monitoring parameters should not exceed 5%. The control mechanism is shown in Table 1 below. For the convenience of explaining the mechanism, the water quality parameters are shown in pH:

[0053] Table 1 Flow and water quality online monitoring and control mechanism

[0054]

[0055]

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) This technology is a digital application innovation in the field of soil leaching. It integrates the existing online monitoring, data acquisition, configuration analysis and automatic control technologies and applies them to the field of soil leaching, further realizing comprehensive automated control of soil leaching.

[0058] (2) This technology can control the liquid-to-solid ratio of soil feed and elution in real time, monitor water quality in real time, indirectly measure the concentration of the agent in the elution, further clarify the amount of lost agent and the necessary replenishment amount, ensure elution efficiency, and reduce agent costs.

[0059] (3) This technology uses digital technology to achieve intelligent control of the leaching process, forming a real and effective database, which can accumulate application data for the subsequent leaching and remediation of soils with different types of pollution in different regions and form application rules. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic diagram of the composition and flow of the digital elution and dosing circulation system based on sensor technology provided by the present invention;

[0061] Figure 2 The pH standard determination curves for different concentrations of citric acid are shown;

[0062] Figure 3 The pH curves of different concentrations of citric acid eluent at key positions during the elution process are shown. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the implementation of the present invention will be clearly and completely described below in combination with the specific application embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0064] The Cu pollution concentration of a heavy metal-contaminated soil in Shanghai is about 2300mg / kg. 100t is eluted with 0.5% citric acid solution, the liquid-to-solid ratio is 6mL / g, the elution time is 30min, 2t is processed per hour, the heavy metal capture agent dosage is 0.005%, the PAC dosage is 0.05%, and the PAM dosage is 0.005%. The elution system is used for pilot test.

[0065] According to the design, a belt scale is installed on the feed transport device, an electromagnetic flowmeter is installed at the inlet and outlet of the bracket water pool, and an electromagnetic flowmeter and an online pH monitor are set at the dosing port of the water treatment. In the laboratory test, different concentrations of citric acid stock solution are used to elute the soil, and the pH curve of the eluent after elution is obtained, such as Figure 2 , Figure 3 , determine the pH value of the elution wastewater under the condition of 0.5% citric acid dosage.

[0066] This implementation case uses the following digital elution and dosing circulation system and method:

[0067] first step:

[0068] The pilot test determined that the water quality parameter that can reflect the concentration of C0, C1, and C2 citric acid is pH;

[0069] The fitting function of C0(x) and pH(y) is determined as follows:

[0070] y=4.49-0.445ln(x-0.097), R 2 =0.91017

[0071] The fitting function of C1(x) and pH(y) is determined as follows:

[0072] y=8.91-0.598ln(x+0.56),R 2 =0.9092

[0073] The fitting function of C2(x) and pH(y) is determined as follows:

[0074] y=2.172-0.402ln(x+0.05),R 2 =0.91486

[0075] The reagent replenishment ratio was determined to be 20% of the original eluent, which could still meet the Cu removal target under circulating conditions.

[0076] Step 2:

[0077] S1: The soil feed is weighed to obtain the real-time soil feed rate S (t / h). The feed rate is controlled to be within ±10% of the theoretical value. The water flow rate Q0 is controlled to be within ±10% of the theoretical value according to the liquid-solid ratio and the valve. Q0 = S × liquid-solid ratio;

[0078] S2: The elution wastewater enters the bracket pool after water treatment, and the elution agent and clean water are replenished at the bracket pool; C0, C1, and C2 are indirectly measured through water quality monitoring at the three inlets and one outlet of the bracket pool, and Q2 is adjusted using an automatic control program to control C0, C1, and C2 within a deviation of ±10% of the theoretical value.

[0079] S3: Automatically adjust the clean water flow Q3 according to the conditions of Q0, Q1, and Q2 to complete the water circulation and chemical supplement for soil leaching and wastewater treatment to achieve dynamic balance.

[0080] S4: Through the monitoring input values ​​and fitting functions of water quality parameters at different locations in the configuration simulation software, the cumulative monitoring calculation of the input reagents is carried out, as shown in Table 2 below:

[0081] Table 2 Summary of online monitoring of eluent flow and water quality

[0082]

[0083] Application effect: After the system has been running for 1, 2, and 3 hours, the soil after leaching and filtration is sampled to analyze the change in Cu concentration in the soil after leaching. The results show that the concentration of Cu in the soil after leaching is between 1504 and 1532 mg / kg, the removal rate is stable, and the requirement of the remediation target value of 2000 mg / kg is met. The cumulative dosage of the agent is This result shows that the stable dosage formed by the digital leaching and dosing circulation system based on sensor technology of the present invention is effective and can maintain the operation of the system and continuous and effective remediation.

[0084] The preferred embodiments of the present invention have been specifically described above, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A digital elution and dosing circulation system based on sensor technology, characterized in that: Including soil washing system, water treatment system and monitoring system, The soil leaching system is used to perform leaching and remediation on heavy metal contaminated soil, and includes a feeding unit, a drum screening, a vibration screening, a cyclone classification and cyclone elution, and a dehydration unit; The water treatment system is used to reuse the leaching wastewater, and includes a regulating tank, a dosing tank, a sedimentation tank, and a support tank connected in sequence, and the inlet of the regulating tank is connected to the outlet of the dehydration unit; The monitoring system includes weighing monitoring of the feed unit, inflow and outflow monitoring of the support pool area, and water quality monitoring.

2. The digital elution and dosing circulation system based on sensor technology according to claim 1 is characterized in that: in, The feeding unit includes an ALLU hopper, an upper hopper and a conveyor connected in sequence, and a weighing monitor is installed on the conveyor to monitor the feeding amount S of the heavy metal contaminated soil; The water outlet of the support water pool is connected to the feed port of the drum screen; the mud outlet of the drum screen is connected to the inlet of the vibrating screen, and the mud outlet of the vibrating screen is connected to the cyclone classification and cyclone elution inlets; The cyclone classification and cyclone elution include primary cyclone elution, primary cyclone separation, secondary cyclone elution, secondary cyclone separation and mechanical stirring elution; the dehydration unit includes a dehydration screen, a cyclone concentration and a plate and frame filter press; The primary cyclone elution inlet is connected to the slurry outlet of the vibrating screen, the primary cyclone elution outlet is connected to the primary cyclone sorting inlet, the coarse material outlet of the primary cyclone sorting is connected to the mechanical stirring elution, and the fine material outlet is connected to the secondary cyclone elution inlet; The mechanical stirring elution outlet is connected to the secondary cyclone sorting inlet, the coarse material outlet of the secondary cyclone sorting is connected to the dewatering screen, and the fine material outlet is connected to the secondary cyclone elution inlet; The outlet of the secondary cyclone elution is connected to the cyclone concentration, the supernatant outlet of the cyclone concentration is connected to the inlet of the regulating tank, the sludge outlet of the cyclone concentration is connected to the inlet of the plate and frame filter press, and the wastewater outlet of the plate and frame filter press is connected to the regulating tank of the water treatment system.

3. The digital elution and dosing circulation system based on sensor technology according to claim 1 is characterized in that: in, Three inlet flow rates and two water quality monitors are arranged at the inlet of the support water pool, and one outlet flow rate and one water quality monitor are arranged at the outlet: the outlet flow rate and water quality are the adjusted eluent Q0 and f(C0) in the support water pool; the three inlet flow rates and two water qualities are: ① sedimentation tank effluent Q1 and f(C1), ② supplementary eluent Q2 and f(C2), ③ clean water Q3; Q0, Q1, Q2, and Q3 are monitored in real time and data is transmitted by an electromagnetic flowmeter, and f(C0), f(C1), and f(C2) are monitored, processed, and data is transmitted in real time by corresponding water quality sensors.

4. The digital elution and dosing circulation system based on sensor technology according to claim 3 is characterized in that: in, The support pool can store at least 1.5h of eluent for continuous operation. The volume of the support pool must meet the condition V≥1.5×Q0. The water quality is selected from pH, conductivity, COD, turbidity or chromaticity, and the concentration value is obtained by reverse calculation based on a fitting curve between the water quality and the concentration.

5. A digital elution and dosing circulation method based on sensor technology, characterized in that: The steps include: S1: The soil feed is weighed to obtain the real-time soil feed rate S (t / h). The feed rate is controlled to be within ±10% of the theoretical value. The water flow rate Q0 is controlled to be within ±10% of the theoretical value according to the liquid-solid ratio and the valve. Q0 = S × liquid-solid ratio; S2: The leaching wastewater enters the bracket pool after water treatment, and the leaching agent and clean water are supplemented at the bracket pool; f(C0), f(C1), and f(C2) are measured by water quality monitoring at the three inlets and one outlet of the bracket pool, and Q2 is adjusted by the automatic control program to control the monitoring values ​​within the deviation of ±10% of the theoretical value; S3: Automatically adjust the clean water flow Q3 according to the conditions of Q0, Q1, and Q2 to complete the water circulation and reagent supplement for soil leaching and wastewater treatment to achieve dynamic balance; S4: Through the monitoring input values ​​and fitting functions of water quality parameters at different locations in the configuration simulation software, cumulative monitoring calculations are performed on the input reagents.

6. The digital elution and dosing circulation method based on sensor technology according to claim 5 is characterized in that: in, The ratio of the outlet water flow Q0 to S is maintained at 4:1 to 6:

1.

7. The digital elution and dosing circulation method based on sensor technology according to claim 5 is characterized in that: The types of eluents and the methods for monitoring flow and water quality are as follows: (1) Determine the feed rate of contaminated soil according to the treatment capacity of the leaching equipment, and design the type and concentration of the leaching agent, liquid-to-solid ratio and water treatment plan according to the soil pollution characteristics and soil texture; (2) Determine the concentration-water quality curve of the eluent, fit the concentration-water quality fitting function of the specific eluent according to the measurement results, and select the water quality type with the best fitting effect; (3) Carry out a small-scale leaching test according to the designed liquid-solid ratio, and measure the water quality of the leaching waste liquid after leaching filtration and the leaching regeneration liquid after water treatment, respectively, to obtain the concentration-water quality curve of the two process nodes. The concentration is the concentration of the leaching stock solution. The concentration-water quality fitting function of the process node is obtained according to the measurement results, and the water quality type with the best fitting effect is selected; (4) Determine the optimal amount of reagent supplement for the elution regeneration liquid after water treatment, select elution stock solutions with different concentration gradients of 0%, 10%, 20%, 30%, 40%, and 50% as the supplement amount to be added to the elution regeneration liquid after water treatment, and use it as the elution liquid for circulating elution to conduct soil elution test, measure the pollutant content of the soil after elution, and determine the amount of reagent supplement that can meet the pollutant removal rate; (5) Determine the replenishment amount-water quality curve of the circulating eluent under different reagent replenishment conditions, obtain the eluent replenishment amount-water quality fitting function based on the measurement results, and select the water quality type with the best fitting effect based on the degree of fit; (6) All the above water qualities are water qualities that can be quickly and directly monitored, including pH, conductivity, COD, turbidity, and color. The fitting results in steps (3) to (5) are the results of repeating the elution process for more than 3 cycles and more than 2 control groups. The fitting coefficient R 2 >0.9; (7) According to the above steps, determine the eluent and concentration required for eluting the specific contaminated soil, the theoretical value of the soil feed amount S, the liquid-to-solid ratio and the theoretical value of the eluent flow rate Q0; (8) Determine the amount of reagent supplement under the circulating elution conditions, determine the water quality types of the reaction water treatment effluent f(C1), the supplementary reagent effluent f(C2), and the circulating elution liquid effluent f(C0), the required sensors, the fitting function relationship and the theoretical value.

8. The digital elution and dosing circulation method based on sensor technology according to claim 5, Features: The soil treatment steps are as follows: heavy metal contaminated soil is screened by the ALLU bucket to remove construction waste from the soil, and after the drum screening unit screens out stones of 3 to 20 mm, it is mixed with the eluent provided by the support pool according to the designed liquid-solid ratio to make slurry, and then high-frequency vibration screening is performed to remove sand and gravel with a particle size of about 1.5 to 3 mm; After the initial screening, the mud enters the cyclone classification and cyclone elution stage. The mixed mud first undergoes high-intensity physical elution at the primary cyclone elution to ensure sufficient mixing and reaction of the granular material and the eluent; then it enters the primary cyclone sorting to separate the particles with a diameter of more than 0.075 mm, and the fine materials below 0.075 mm enter the secondary cyclone elution for further mixing and reaction. The coarse particles enter the stirring elution device for elution and then enter the secondary cyclone sorting device for further classification; after the secondary cyclone sorting, the coarse materials are dehydrated in the dewatering screen to obtain fine sand with a diameter of 0.075 to 1.5 mm. After the secondary cyclone sorting, the fine materials enter the secondary cyclone elution for further elution; The mud after secondary cyclone elution is pre-dehydrated by cyclone concentration, and then deeply dehydrated by plate and frame filter press to form clean soil mud cake; the effluent from the filtration enters the regulating tank, and after the addition of chemicals and precipitation, the treated clear liquid flows into the support pool for storage; the clear liquid is supplemented with chemicals and clean water in the support pool and then pumped to the drum screen to mix with the contaminated soil of the feed for pulping.

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